Annular receptacle for a rotating carrier

ABSTRACT

An annular receptacle is described, particularly for a rotating carrier for receiving a disk-shaped object such as a semiconductor.

FIELD OF THE INVENTION

[0001] The present invention relates to an annular receptacle,particularly for a rotating carrier for receiving a disk-shaped objectsuch as a semiconductor. Insofar as semiconductors or wafers arementioned in the following, this concept includes all types ofdisk-shaped objects such as CDs or magnetic disks

BACKGROUND OF THE INVENTION

[0002] For processing disk-shaped semiconductors, for example foretching silicon disks (wafers), possibly using different acids,positioning the semiconductor on a rotating carrier (chuck) is known. Atreatment liquid, for example an acid, is applied to the surface of thesemiconductor to be treated. The etching liquid distributes itself overthis surface due to the rotational movement of the semiconductor and isaccelerated laterally (radially) over the edge of the semiconductor.

[0003] For catching this treatment liquid, it is suggested, in EuropeanPatent 0 444 714 B1, that at least two ring channels, which are open tothe inside of the receptacle, be provided in the annular receptacle(pot) for collecting the treatment liquid. In other words: the ringchannels are used for the purpose of catching thrown-off processingliquid. Accordingly, the ring channels are arranged in the receptacle ina radial extension of the semiconductor to be treated. In German PatentApplication 198 07 460 A1, an annular receptacle of this species isdescribed which has, in addition to the annular channel, via which thetreatment liquid is removed, at least one suction device. The basic ideaof this known solution is to suction off the processing air (processinggas) located in the system (the facility) separately from the radialabsorption of thrown-off processing liquid.

[0004] However, due to the essentially rotationally symmetricconstruction of the receptacle, the problem of non-uniform suctionperformance results if, as suggested in German Patent Application 198 07460 A1, the processing air collected in the ring channel is suctionedoff via a radially running connection line. In addition, the knownreceptacle is relatively large. Space problems result from this in cleanrooms, where these types of devices are installed. The space necessaryfor a device is a not insignificant influencing dimension for theoverall production costs.

[0005] Finally, the known device requires, due to differing pressureratios (considered over the circumference of the device), a relativelyhigh suction power which may, for example, be up to 1000 m³/h for wafershaving a diameter of 30 cm.

[0006] The present invention therefore has the object of constructivelyoptimizing a device (receptacle) of the type described in order tofulfill at least one, preferably all, of the following criteria:

[0007] The device is to be as small as possible for a defined size ofthe objects to be treated,

[0008] pressure conditions which are as uniform as possible (consideredaround the circumference of the device) are to be sought in regard tothe respective suction device,

[0009] the necessary suction power is to be as low as possible forreasons of cost,

[0010] separation of different treatment media, including the respectiveprocessing atmosphere, which is as precise as possible is to be sought.

[0011] To achieve these and further parts of the object, which resultfrom the remaining application documents, the present invention is basedon the following basic consideration: in an essentially rotationallysymmetric component, such as a receptacle according to the species,uniform pressure ratios may not be achieved in the receptacle with amore or less punctually acting partial vacuum source if the individualsupply lines discharge directly into a joint peripheral channel, whichthe suction line leads away from.

[0012] In contrast, the pressure ratios are greatly improved if theatmosphere to be removed is initially led into a suction chamber andfrom there into a pressure distribution chamber, to which a suction lineis connected.

[0013] The advantages connected with this are particularly clear in“multistory receptacles”, i.e., devices in which the carrier for theobject to be treated is vertically displaceable and different treatmentprocesses are performed at various vertical heights. Thus, for example,in one step a wafer may be etched, and in another step the wafer surfacemay be washed using deionized water. In this case, annular channelscorresponding to each treatment step are assigned, via which therespective processing liquid may be removed. Each annular channel isthen in turn assigned a suction device, which is implemented in the waydescribed in the preceding and following. Multiple suction devicespreferably discharge into one and the same pressure distributionchamber, which causes the suction power to even out, the correspondingpartial vacuum able to occur via a central suction line, as in therelated art.

SUMMARY OF THE INVENTION

[0014] Therefore, the present invention, in its most general embodiment,relates to an annular receptacle for a rotating carrier for receiving adisk-shaped object having the following features:

[0015] The receptacle has at least one annular channel in the radialextension of a supporting surface of the carrier for the object,

[0016] neighboring at least one annular channel, at least one suctiondevice runs in the receptacle starting from its inner wall,

[0017] the suction device includes suction openings positioned in theregion of the inner wall and an annular suction chamber radiallyadjoining the suction end of the suction openings,

[0018] at least one pressure distribution chamber connects a suctionline to the suction chamber.

[0019] Like the objects to be treated, for example, wafers, the deviceis also essentially rotationally symmetric “Essentially rotationallysymmetric” means, in this case, that (with the exception of the centralsuction line) the remaining parts of the device are arranged distributedessentially uniformly around a central lengthwise axis of the device.

[0020] Corresponding to the annular channels, via which thrown offprocessing liquid may be guided away, the suction openings are also, forexample, positioned along a ring surface which may be a direct componentof the inner wall of the receptacle. The suction openings may run aboveand/or below the associated annular channel(s), as is explained in moredetail with reference to the following description of figures. Thesuction openings may be simple holes (bores), but may also be designedlike suction nozzles. Suction slots may also be provided.

[0021] The suction chamber connected downstream from the suctionopenings in the flow direction may adjoin directly to the suctionopenings radially on the outside in a horizontal plane. However,according to one embodiment, at least one suction chamber runs, startingfrom the inner wall of the receptacle, sloping down outward and/or inrelation to the supporting surface of an associated carrier.

[0022] From the suction chamber, the gas suctioned off reaches theconnected pressure distribution chamber via a “baffle” (a locationtapered in cross-section).

[0023] The suction chamber may be connected to the pressure distributionchamber via discrete openings. In other words: like the suction openingsbetween the inner chamber of the receptacle and the suction chamber, theconnections between the suction chamber and the pressure distributionchamber adjoining it in the flow direction may be designed essentiallyas desired.

[0024] In order to optimize evening out of the pressure ratios, however,a rotationally symmetric arrangement of the openings between the suctionchamber and the pressure distribution chamber suggests itself.

[0025] In a receptacle having multiple annular channels running over oneanother in the receptacle and suction devices assigned to them, oneembodiment provides that at least two suction devices, possibly even allsuction devices, are connected to the same pressure distributionchamber. In this way, the processing gases concerned are suctioned offseparately into different suction chambers in individual “stories” ofthe device, but are subsequently fed from there to a joint pressuredistribution chamber, so that as a whole essentially isotropic pressureratios result over the entire facility.

[0026] In this case, it suggests itself, as will be explained in thedescription of the figures, that the pressure distribution chamber beimplemented as a peripheral chamber having a relatively low width whichextends, however, essentially over the entire height of the receptacle.

[0027] Outlet lines may be connected to the individual channels, viawhich the processing liquid is guided away. Alternatively, this may beperformed in such away that the processing liquid is subsequentlyrecirculated, i.e., returned to a spraying device above the disk-shapedobject, for example.

[0028] In this case, multiple annular channels may be connected to ajoint outlet line, particularly if identical or compatible liquids areguided away via the corresponding channels.

[0029] The construction described allows the suction power to be reducedby up to 75% in relation to comparable devices according to the relatedart. This is particularly a consequence of evening out the pressureratios and the optimization of the air conduction. In addition, thereceptacle may be designed compactly and requires very little space. Forexample, for treating wafers having a diameter of 30 cm, externaldiameter of the device may be restricted to approximately 60 cm or less.

[0030] Further features of the present invention result from thefeatures of the dependent claims and the other application documents.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention is described in more detail in thefollowing with reference to an exemplary embodiment. The sole figureshows a longitudinal section through an annular (pot-shaped) multistagereceptacle, without a carrier for the object to be treated, because thisis related art and may, for example, be taken from German PatentApplication 198 07 460 A1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0032] The receptacle has a cylindrical inner chamber 10, which isdelimited by an inner wall 12 of the receptacle. A carrier (not shown)is positioned so it is vertically adjustable in inner chamber 10. Theobject to be treated lies flat on the carrier.

[0033] A first ring zone 14 having suction openings 16, to which acorresponding suction chamber 18 is peripherally (radially) connected,is located in the region of inner wall 12. Openings 20 distributedrotationally symmetrically are positioned in floor 18 b of suctionchamber 18, which discharge into a pressure distribution chamber, whichruns concentrically to central lengthwise axis M of the device and whichhas a height (parallel to central lengthwise axis M) multiple timesgreater than the chamber width (channel width). Pressure distributionchamber 30 is delimited on the lower end by a floor plate 22.

[0034] A further ring zone 14′, which is constructed analogously to ringzone 14, is provided at a distance below (upper) ring zone 14. A ringchamber 18′ adjoins the outside of this ring zone 14′. While ringchamber 18 adjoins ring zone 14 in a horizontal plane, suction chamber18′ slopes downward and outward, starting from ring zone 14′. In thiscase, an approximately triangular cross-sectional profile results,having an essentially vertical external wall in which openings 20′ arepositioned, distributed around the circumference, to which tubularspacers 24 adjoin radially outward in order to provide a throughconnection from suction chamber 18′ to pressure distribution chamber 30.

[0035] An annular channel 26, which adjoins cylindrical inner chamber 10radially outward and essentially runs between suction chambers 18, 18′,is simultaneously delimited between ring zones 14, 14′.

[0036] On the outside, annular channel 26 turns into a channel 28,running parallel to pressure distribution chamber 30, which dischargesinto a type of floor groove 32, which a hose line 34 leads away from.

[0037] As may be seen in the figures, spacers 24 run transverselythrough channel 28 without, however, impairing the vertical flowabilityof channel 28.

[0038] A further ring zone 14″, which is again designed essentiallyanalogously to ring zones 14, 14′, runs at a distance below ring zone14′. Similarly to ring zone 14, a suction chamber 18″ adjoins on theoutside, whose peripheral wall surfaces have openings 20″ to whichspacers 24′ adjoin (as on openings 20′), which provide a flow connectionbetween suction chamber 18″ and pressure distribution chamber 30.

[0039] A further channel 26′ is implemented, between ring zones 14′,14″, which, in addition to a slanted upper wall 26′w, includes a lower,trough-like, peripheral part 26′r, which a spur line 36 leads away from.

[0040] Section 26′r is delimited on the inside by a part 12 u of innerwall 12.

[0041] The device functions, for example, as follows:

[0042] A carrier having a wafer is guided to a position between ringzones 14′, 14″ and driven so it rotates. The wafer is treated from aboveusing an etching liquid which is thrown off outward into channel 26′ andguided away via spur line 36. Simultaneously, the processing air issuctioned off via ring zone 14′ via suction, chamber 18′ and spacers 24into pressure distribution chamber 30 which, as illustrated in the leftpart of the figure, is connected to a central suction line 38.

[0043] Simultaneously, suctioning may also be performed via further ringzones 14, 14″, the entire processing air (although in different ways)discharges into pressure distribution chamber 30 as a result and isdrawn off from there via suction line 38.

[0044] After this processing step, the carrier may be raised and broughtinto a position between ring zones 14, 14′. It may, for example, betreated here using deionized water which is accelerated around thecircumference into channel 26, where it runs via channel 28 into floortrough 32 and is drawn off there via hose line 34.

[0045] A further reduction of the size of the device may be achievedthrough the essentially parallel arrangement of pressure distributionchamber 30 (outlet line for gaseous media) and channel 28 (for guidingaway a processing liquid)

1. An annular receptacle for a rotating carrier to receive a disk-shapedobject having the following features: 1.1 the receptacle has at leastone annular charnel (26, 26′) in the radial extension of a supportingsurface of the carrier for the object, 1.2 neighboring at least oneannular channel (26, 26′), at least one suction device runs in thereceptacle, starting from its inner wall (12), 1.3 the suction deviceincludes 1.3.1 suction openings (16) positioned in the region of theinner wall (12), 1.3.2 an annular suction chamber (18, 8′, 18″) radiallyadjoining the suction end of the suction openings (16), 1.4 a pressuredistribution chamber (30) connects a suction line (38) to the suctionchamber (18, 18′, 18″).
 2. The receptacle according to claim 1, whereinthe suction openings (16) run above the annular channel (26, 26′). 3.The receptacle according to claim 1, wherein the suction openings (16)comprise multiple suction nozzles distributed as uniformly as possiblealong the inner wall (12) of the receptacle.
 4. The receptacle accordingto claim 1, wherein the suction openings (16) are positioned on a ringsurface (14, 14′, 14″).
 5. The receptacle according to claim 1, whereinthe suction chamber (18, 18′, 18″) is connected to the pressuredistribution chamber (30) via discrete openings (20, 20′, 20″).
 6. Thereceptacle according to claim 1 having multiple annular channels (26,26′), which run on top of one another in the receptacle, and suctiondevices assigned to them, at least two suction devices being connectedto the same pressure distribution chamber (30).
 7. The receptacleaccording to claim 1, wherein the suction chamber (18′) of at least onesuction device slopes downward in relation to the supporting surface ofthe carrier, starting from the inner wall (12) of the receptacle.
 8. Thereceptacle according to claim 1 having an outlet line (34, 36),connected to an annular channel (26, 26′), which is alternativelyreturned to a spraying device above the disk-shaped object.
 9. Thereceptacle according to claim 8, wherein multiple annular channels (26,26′) are connected to a joint outlet line.
 10. The receptacle accordingto claim 1, wherein the pressure distribution chamber (30) has arelatively small width, but extends over essentially the entire heightof the receptacle